Apparatus for traffic control



2 Sheets-Sheet 1 R. H. WORRALL APPARATUS FOR TRAFFIC CONTROL Filed Jan. 30, 19553 n m ET H A M w m 7 3 2 u w w 4 M E E M a w I W B W fk I 7. w. w m E s r u T N a D E r 3 H 4 v T a m u e llllLl A 4 lllll m a pm Y n m u 1 0 3 W 9 1 n w a 5 4 m .M G l M k A A A 8 E W 6 1R L J W 4 w AHW 9 Q 1@ Wm? r a 1 W 1 v M w f a A M 5 TH: HE: Hv 6c r I [MCI E J l U f U C a R ,G B H P June 4, 1935.

June 4, 1935. R. H. WORRALL APPARATUS FOR TRAFFIC CONTROL Filed Jan. 30, 1933 2 Sheets-Sheet 2 INVINTOR Robert H. Warren! A TTORNEY T0 POWER SUPPLY A. C.

FEED T0 ENTIRE SYJTG'M ha tentecl June 4, 1935 r p v UNITED STATES PATENT OFFICE APPARATUS FOR TRAFFIC CONTROL Robert lL-worrall, Washington, D. 0. Application January 30, 1933, Serial No. 654,201

1 Claim. (01. 177-337) (Granted under the act of March 3, 1883, as amended April 30, 1928; 370 O. G. 757) This application is a continuation in part of This system is designed to control tramc at an my application Serial No. 551,187 filed July 16, intersection of two routes, for example, anorth- 1931. south route and an east-west route. Assume that This invention relates to improvements in a there is no traific on the east-west route but 5 method of and apparatus for trafllc control in that control is still with the circuits associated 5 which the operation of the traflic lightsis affected W s route- A m c approaches this by the frequency of interruption, by passing veintersection on the north-south route and upon hicles, of a beam of light which is acting upon P ssing a point on the road before arriving at a light Sensitive eell- V the intersection, a relay is tripped through 'the An object of thi inventi i t provide a medium of alight sensitive cell, or other methods 10 method of trafllc control in hi h, at a tr t described later on. As the control is in the intersection, preference is automatically and proast-w t route for 'a'e v l th f tim say portionately given to the street which has the fi s ds, n thi happ s until t P d greatest tram g haselapsed. Then the control shifts to the Another object of this invention is to provide north-South route which gets a green 1 8m. 1 a 1 apparatus for traffic control in which, at a street car DeSSeS along the north-South u e eve y I011! intersection, preference is automatically and pro- Seconds for tWO minutes the control w l t y portionately given t t t t which s t with-the north-south route for that time and greatesttraffic. upon a five-second gap at the expiration of that Present day trafllc control consists of lights at time it will Shift to the east-west mute 888111 a street intersection which allow trafllc to flow which ll get a green light while the northfor a given length of time along one street and South route will have a red i s long as then for a given length of time along the other cars come 510118 every 10111 Seconds less. the street control will remain with that route for a prede- In case there is no tram on one treet; any termined length of time when allto- 26 trafiic there'may be on the other street is forced flh the other mum If no lire-me comes to wait until the signal favors them. So, any along 81th" route the lights will ehahfie every fixed adjustment of the timing of the lights must fivesecondsin both Streets. the beams of necessarily be decided upon by a comparison of h acting the light sensitive cells are 30 the average traffic on the two streets. To show a Interrupted and remain blocked, the mute which 30 favorable light to a street with no traffic on it control would keepcohtl'ol until the when there a large amount f tramc on its time limit relay functions and when the traffic tersecting street creates a very unsatisfactory moved the control circuits would fuhetien as condition of traffic congestion. What is needed fore: Should one name light bum out, the Whole is a trafiic control system that will automatically system wouldhhut 35 respond to the fluctuations in tramc on the inter- Further oblects of h lhvehtioh will p secting streets and proportionately give perferin the suhsequeht detahed descriptionence to the street having the greater trafllc. This I Prachse my method attalh these obleets is accomplished by the following described circuit. by t e e -i illustrated m the accompanying 40 When trafiic is moving on one street of the drawmgsr which: intersection, the corresponding circuit hascon- 1 is B diagrammatic ke ch showing the trol and allows trafllc to flow as long as there is no complete circuits as applied to two through gap in the stream of cars greater than a given streets; time interval, say five seconds. Should. such a V Fig 2 is diagrammatic sketch of the m gap occur, the signal lights will change, giving the control circuits; 5 other street the right of way. In case tramc Fig 3 is a diagrammatic sketch Showing a should be so heavy on one street that no fivetem of power supply and the method of cutting second gap occurs, the control remains with the out the entire system m case 118mb traffic until a time limit relay functions. This out time relay may be set for any desired ime, say

five minutes, whence the lights will change and The trams control systhmr 2, is composed the control will be given to the circuit associated the following circuits! with the other street. This typeof control keeps A ce Steady light and current pp y trafllc moving and reduces accumulative congesfor same ID and duplicate circuit H tion which otherwise would occur. A light sensitive cell I! in series with a relay 6 52 and battery I6 and duplicate circuits I3, 53

and I1;

A control circuit comprising battery I8, wire 54, contact 55, armature I4, wire 58, wire 51, armature 58, contact 59 or (contact 68 and wire 6|), wire 82 and solenoid 63; and duplicate control circuit comprising battery I9, solenoid 64, wire 85, armature I5, contact 66, wire 61, contact 68 or (wire 18 and contact 69), wire 12 and wire 13.

A light and control shifting circuit comprising battery 22, wire 82, contact arm 14, contact are 15, wire 16, wire 51, armature 58, contact 11, wire 18, relay 26, wire 19, relay 24, wire 88, time limit relay 38, contact arm I62, contact are I63 and wire BI; and duplicate light and control shifting circuit comprising battery 23, wire 83, contact arm 84, contact are 85, wire 86, wire 12, armature 1|, contact 81, wire 88, relay 21, wire 89, relay 25, wire 98, time limit relay 3|, contact arm I64, contact arc I65 and wire 9|.

A signal light circuit comprising battery 28, wire 92, light G, wire 93, contact 94, armature 95 and wire I81, orbattery 28, wire .96, light R, wire 91, contact 98, armature 95 and wire I81; andduplicate circuit comprising battery 29, wire 99, light G, wire I88, contact |8I, armature I82 and wire I86, or battery 29, wire I83, light R, wire I84, contactl85, armature I82 and wire I86.

Referring to Fig. 2, the circuit that is first turned on willtake control. Assuming this to be the uper one, the beam of light from source I8 strikes light sensitive cell I2, causing armature I4 to make contact with 55 closing the circuit from battery I8, wire 54, contact 55, wire 56, wire 51, armature 58, contact 59, wire 82 and solenoid 63 which through its armature 28 moves contact .arms '14 slowly from right to left toward the ofi position, the motion of arm 14 being retarded'by dash pot. I23. While contact arm 14 is on contact are 15, current flows through battery 22, wire 82, contact arm 14, contact are 15, wire 18, wire 51, armature 58,. contact 11, wire 18, relay 26,

wire 19, relay 24, wire 88, time limit relay 38, contact arm I62, contact are I63 and wire 8|. Relay 26 being energized holds armature II against contact 68 and relay 24, being energized,

holds armature 95 against contact 94, causing the upper green light to be lighted. The corresponding circuit through battery 23, wire 83, contact-arm 84, contact are 85, wire 88, wire 12, armature 1I, contact 81, wire 88, relay 21, wire 89, relay 25, wire '98, time limit relay 3|, contact arm I64, contact are I and wire 9| is interrupted at contact81 which is open and may also be interrupted by contact arm 84 being in the oil position. There being no current through relay 21, the armature 58 by its spring is held against contacts 59 and 11 and there being no current through 'relay 25, armature I 82 makes contact with I85, causing the lower red light to be lighted. During this condition, if the light from source II is not interrupted, arm 84 will be held in the off position, the solenoid 64 being energized through wire 65, armature I5, contact 88, wire 81, contact 68 (relay 26 being energized), wire 13 and battery I9; and if light source II is interrupted, the arm 84 by its spring will be moved to the on position. But this will have no eiiect on circuit 23, 83, 84, 85, 86, II, 81, 88, 21, 89, 25, 98, 3|, I64, I85 and 9I-which remains open-circuited during this condition at contact 81. And when the circuit 22, 82, 14,15, 16, 51, 58, 11, 18, 26, 19, 24, 88, 38, |62, I63 and 8| is I9, 64, 65, I5, 66, 61, 68 (open), 'II, "I2, 13, de-

energizing solenoid 64 and, regardless of the position of arm 84, insuring its setting by its spring to the beginning of its on position. When armature 1| contacts with contact 81, the circuit 23, 83, 84, 85, 86, 1|, 81, 88, 21, 89, 25, 98, 3| I64, I65 and 9| is energized, relay 21 moving armature 56 to the left against contact 68 and relay 25 moving armature I82 against contact |8I, causing the lower green light to be lighted and the lower red'light to be extinguished by interrupting its circuit 29, I82, I85, I84, R, I83 at contact I85. When armature 58 opened contact 11, it insured the interruption of circuit 22, 82, 14, 15, 16, 51, 58,11 (open), 18, 26, 19, 24, 88, 38, I62, I63 and 8| regardless of the position of arm 14. This leaves relay 24 de-energized, opening contact 94 and closing contact 98 thus extinguishing the upper green light and causing the upper red light to be lighted.

While the upper circuit has control it will maintain such control for five seconds and if at the end of that interval no car has interrupted the beam of light from I8, the arm 14 reaches the oil position, breaks the upper circuit allowing the armature 1| to open contact 68 and to close contacts 69 and 81 and the arm 84 to move to the on'position closing the lower circuit, and the contact '98 of relay 24 to close lighting the upper red instead of the upper green light. As soon as current flows through the lower circuit, it closes the contact I 8| of relay 25, lighting the lower green instead of the lower red light, and closes the front contact 68 of relay 21. Thus, assuming no cause of interruption between light'sources I8 and II and their respective cells I2 and I3, which corresponds to a condition of no traflic, the control will pass from one circuit to the other every 5 seconds accompanied with a corresponding change in lights. However, if, before the five-second interval has expired, a car interrupts the beam of light from I 8, armature I4 will open contact 55, breaking thecurrent in solenoid 63, allowing arm 14 to' move to the beginning of the on position, and begin another five-second period. In this manf ner the upper circuit can maintain control as long as it has a steady stream of traflic, but will shift to the lower circuit if a five-second period lapses without an interuption of the beam from I8. When the lower circuit has control andtraflic on that route continues, it likewise will maintain control.

If continuous trafiic prevails on the route'for the upper circuit for any predetermined period, such as five minutes, then time limit relay 38- will operate giving control to the lower circuit. The same is true of the lower circuit where, at the expiration of five minutes continues traflic,

time limit relay 3| will give control to the upper being considerably greater than that of the opposing spring, the contact arm I62 because of such sudden release will begin to move rapidly and when it breaks contact with contact are I63 and time relay 30 is de-energized, the inertia of contact arm I62 will carry it on a space sufficient to insure that the contact with contact are I63 isbroken. Such downward movement of the contact arm is not resisted by dash pot I66 but it does resist the return upward movement under the influence of the spring. The contact must remain open a fraction of a second to allow sufficient time for armature H to move from left to right to throw control to the lower circuit. The dash pot I66 creates a three-second delay in the return of contact arm I62 to its initial position. This delay must be less than five seconds to insure the resetting of the contact arm before the earliest period at which control could be returned to the upper circuit. During its upward movement the contact arm is not opposed by dash pot I61.

The operation of time limit relay 3I is similar to that of relay 30.

For the circuit shown in Fig. 1, the fundamental operation is the same as that described for Fig. 2.

The control circuits associated with the northsouth street are: A control circuit comprising battery 46, wire I06, wire I09, contact H0, armature III, wire H2, armature H3, contact H4, wire H5, solenoid H6, wire II1, contact H6 (or contact I24), armature H9 and wire I20; and a light and control shifting circuit comprising battery 46, wires I08 and I2I, contact arc I22, contact arm I25, wire I26, contact are I69, contact arm I10, time limit relay 46, wire I21, relay 42, wire I28, relay 44, wire I29, contact I30, armature H9 and wire I20.

The control circuits associated with the eastwest street are: A control circuit comprising battery 41, wire I3I, armature I44, contact I32 (or contact I33), wire I34, solenoid I35, wire I36,

contact I31, armature I36, wire I39, armature I40,

contact I, wire I42 and wire I43; and a light and control shifting circuit comprising battery 41, wire I3I, armature I44, contact I45, wire I46,

relay 45, wire I41, relay 43, wire I46, time limit relay 49, contact arm I1I, contact are I12, wire I49, contact arml50, contact are I5I, wire I52 and wire I 43.

The lighting circuits are: A circuit comprising battery I6I, wire I53, armature I54, contact I55, wire I56, lights R and G'and wire I51; and another circuit comprising battery I6I, armature I58, contact I59, wire I60, lights R and G and wire I51.

In Fig. 1, sources of light 32, 33, 34 and 35 would actually be placed at the center of their respective streets, and light sensitive cells with their relay circuits 36, 31, 36 and 39 would be placed respectively on that side of the street which is right for trafiic approaching the intersection, so that only when a car approaches the intersection does it interrupt a beam of light, but in passing on across or turning right or left it does not interrupt the other beams of light.

When east-west has control, an interruption of either beam 32-36 or beam 3331 will reset the arm I60 to the on" position. The contacts I and I33 are closed, the contact I24 is closed, and I55 is open. The contact I59 is closed, lighting lights G and R.

When the arm I reaches the "off position or time limit relay 49 functions, the control is shifted to the north-south routes. This sets the arm I25 to the on position if not already there, allows contacts I30 and -H8 to close, opens I59 and closes I32. It also closes the contact I of relay 43lighting lights G and R. The control remains with the north-south route until I25 reaches the oil position or time limit relay 46 functions. Both time limit relays 46 and 49 function similarly to time limit relay 30 described above. The control shifts back and forth automatically and proportionately to the amount of trafiic on the intersecting streets.

In Figs. 1 and 2, for simplicity, batteries have been shown as sources of energy. Actually, the circuits. would be energized by the'local lighting system. When so energized, Fig. 3 shows a method of cutting out all the lights incase one is burned out. All lights are in parallel and each light is fed through a no-voltage release 50, whose contacts are all in series with the primary of the transformer which'feeds the entire system. If one light burns out and its no-voltage release drops, the primary of the transformer is opened, shutting off the entire system. After the light is replaced, the switch 5| is momentarily closed, lighting all lights and closing the no-voltage releases which restores the circuit to its normal state.

Referring to Fig, l, the circuit 46, I08, I2I, I22, I25, I26, I69, I10, 48, I21, 42, I28, 44, I29, I30, H9, I20 being closed, contacts I59, I45 and I33 are open and contact I55 is closed, causing the lights R and G to be lighted. As the above mentioned circuit is interrupted by time limit relay 46 or arm I25 reaching the off position, the armatures I58 and I44 are moved by their respective springs. In the meantime, armature I54 due to its spring still makes contact with I55 and this contact will not be broken until armature I44 makes contact with I45 energizing circuit 41, I3I I44, I45, I46, 45, I41, 43, I48, 49, HI, I12, I49, I50, I5I, I52 and I43. But by that time armature I58 will have made contact with I59, causing the lights R and G to be lighted. So that for a very short period all signal lights will be lighted and serve as a warning of a change. The contacts I59 being closed before contact I55 is opened and vice versa, contact I55 being closed before I59 is opened, it is clear that at no time, due to the operation of the signaling system, have the novoltage releases 50 an opportunity to function, but

as soon as one light burns out, these no-voltage releases will function to open the circuits to all the signal lights. This is advantageous to prevent accidents. Suppose a car on each street is approaching the intersection and the one which according to the traflic rules would have a rightof-way is supposed to have a red light but the red light is burned out, the other car having a favorable green light continues into the intersection, and the one thinking the trafiic laws control, not knowing of the signal lights, also continues into the intersection and a collision results. It is evident that it would be dangerous to operate such a traflic system without some such cutting-of! device.

There are other means for operating the relays by passing cars, such as through the medium of a vacuum tube bridge circuit, where a change in capacity would cause a current to flow operating the relay; or an oscillating vacuum tube circuit where a change in capacity would cause the circuit to oscillate and current to flow operating the relay.

While in the foregoing there has been illustrated and described such combination and arrangement of elements as constitute the preferred embodiment of my invention, it isnevertheless desired to emphasize-the fact that interpretation of the invention should be conclusive only-when, made in the light of the subjoined claim.

v The herein described invention may .be-m'anufactured and used by or for the Government of the United States of America. for governmental purposes without the payment of any royalties thereon.' I

I claim: l

In a traific control system for intersecting streets,: a go signal and a stop signal for each street, a switch arm individual to each street, a contact are with an insulating segment at one end over which said switch arm is adapted to pass, spring means for moving said armin one direction, electromagnet means for moving said arm in the other direction toward the insulating segment, means associated with said arm opposing said electromagnetic means for controlling .the passing of said. arm over said are with respect to a predetermined interval of time, means comprising traffic actuated devices for deenergizing said electromagnetic means permittingsaidspring means to move'said switch arm, a signal and control'shifting circuit associated with each street comprising a signal shifting relay, a time delay relay and an interlocking relay in series with said switch arm, contact are and a source of potential, said interlocking relay in the said signal and control shifting cir cuit of one street having a front contact and a back contact each of which energizes the said switch arm electromagnetic -means associated with the other street and another back contact which closes the control circuit associated with the said other street, said time delay relay and said insulating segment operating to open said signal and control shiftingcircuit and said interlocking relay, in moving from its front to its back contacts, operatingto shift control tothe 20 other control circuit. 7

ROBERT rr. WORRALL. 

